Well if the webcam showed the UFO you'd have something. But it doesn't so I guess the hoax explanation is the most likely one.

Well!...what do ya know? the webcam
does show, >THE FLASH!!< but I didn't see the ufo light,the large
white glow,that shot straight up
in the blink of an eye!...?
Very shaky grounds though,all this!
BUT!....the webcam, doesn't lie!
does it?...? it does shows, that something was going on!.......?

Where does it show the flash, where does it show that anything unusual was going on? Ok, there is a small dot of light, but that could really be anything. This video proves actually nothing at all. By now i think this whole case is a hoax. A few people made videos from different angles, edited the UFO and the flash of light into it (with an good amount of effort) and released that stuff nearly simultaneously. Get used to it that there are less unaltered (or just good, i.e. that they don't show just a normal airplane) UFO videos on the web than there are actually UFO cases which have been analysed and can't be explained.

It's still pictures taken by the webcam. Looks like one of the stills happens to show the flash, indicating the flashes in the videos to be real. Maybe the ufo was not in the field of view of the webcam when it snapped the picture, but the flash was.

I don't think you can see the flash on this video. You can see a lit up courtyard for a short while, but that's it. Besides, the webcam only takes one picture per minute. Given that the flash in the other videos took approximately 1 second, the chance to see the flash on the webcam footage is about 1/60, that is .017 and therefore pretty unlikely.